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Take Our Test: Are You a Logical Thinker?

The best way to understand the principles of logic, and to become a logical thinker is to actually do some logic. For example, can you work out the conclusion from these two premises? 1. All humans are mortal. 2. Socrates is human. Therefore? Yes, Socrates is mortal. The following 10 logical problems can all be solved by the same careful and considered thought, yet most people get a lot of them wrong. Let’s see how well you do. Just remember to ask yourself: "If these premises are true, what else must be true?"
 
 
 
Some cavemen make use of fire. Everyone who makes use of fire is intelligent. Therefore...
Perhaps they are all intelligent, but we can't deduce this from the premise because we are only certain that some of them use fire.
All cavemen are intelligent.
Everyone who makes use of fire is intelligent.
Some cavemen are intelligent.
None of these logically follow.
 
 
If someone oversleeps, they'll be late. Today they are not late. Therefore...
This type of reasoning is known as Modus Tollens. If A then B. Not B. So not A.
They overslept.
They didn't oversleep.
They are late.
None of these logically follows.
 
 
No one who's been detained for murder has been given bail. Smith is not being held for murder. Therefore...
We don't have enough information to infer that he's been bailed or not.
Smith has been given bail.
smith hasn't been given bail.
Smith is innocent.
None of these logically follows.
 
 
No court which denies or suppresses evidence is impartial. Some courts are subject to political influence and do suppress evidence. Therefore...
The second premise shows that some courts subject to influence suppress evidence. The first premise shows that such courts are not impartial. So some courts subject to political influence are not impartial.
Some courts subject to political influence are not impartial.
No courts that are subject to political influence are impartial.
Some courts subject to political influence are impartial.
None of these logically follows.
 
 
If you oversleep, you'll be late. You did not oversleep. Therefore...
If-then problems can only show us what would happen if the 'if' were true. We can't know what happens if the 'if' is false.
You're not late.
You overslept.
You're late.
None of these logically follows.
 
 
All revolutions disrupt trade. Some disruptions of trade cause financial worries. Therefore...
We cannot draw any conclusions from the premises given here.
Some revolutions cause financial worries.
Some revolutions do not cause financial worries.
All disruptions of trade cause financial worries.
None of these logically follows.
 
 
Any person who's just lost lots of blood will probably faint. Nobody who has a high probability of fainting is a safe pilot. Therefore...
The first premise shows that if you lose blood you may faint. The second premise shows if you might faint, you wouldn't be a safe pilot. Thus, if you had just lost lots of blood, you wouldn't be a safe pilot.
Everyone who's lost lots of blood is a safe pilot.
Nobody who's just lost lots of blood is a safe pilot.
Every safe pilot has recently lost lots of blood.
None of these logically follows.
 
 
If knowledge exists, either some things are known with no proof or we are able to prove every premise by a previous argument indefinitely. We can not prove every premise by previous arguments indefinitely. Knowledge does exist. Therefore...
The first logician, Aristotle, used this argument in order to show that every argument rests in unproven premises.
Everything that is known is provable.
There is no knowledge.
Some things are known without any proof.
None of these logically follows.
 
 
No one who wishes to help other people is reluctant to make sacrifices. Some masochistic people are not reluctant to make sacrifices. Therefore...
From the above premises, we can conclude nothing.
Some masochistic people wish to help other people.
Some masochistic people don't wish to help others.
All masochistic people wish to help others.
None of these logically follows.
 
 
Only those who use languages make generalizations. No animals use language. Some animals reason. Therefore...
Philosopher J.S. Mill used this problem to show that reasoning requires no generalizations (any statement with 'all' or 'no').
Not every reasoning being makes generalizations.
Only reasoning beings make generalizations.
No reasoning being makes generalizations.
None of these validly follows.
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